Problem: Simplify the following expression: $z = \dfrac{y}{8} + \dfrac{3y}{2}$
In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $8$ and $2$ $\lcm(8, 2) = 8$ $ z = \dfrac{1}{1} \cdot \dfrac{y}{8} + \dfrac{4}{4} \cdot \dfrac{3y}{2} $ $z = \dfrac{y}{8} + \dfrac{12y}{8}$ $z = \dfrac{y +12y}{8}$ $z = \dfrac{13y}{8}$